A couple of months ago, I couldn't add any new categories or sub-categories to my site. After two months the issue had been fixed, so I thought. After adding categories and adding product to my site for a week now, this morning all those categories & sub-categories are now missing and I can't add any new categories. This is so irritating. I have been publishing the page everyday work was done. I thought once published it would have been saved. I am trying to get my site up and running but have run into nothing but setbacks.
Sorry for the trouble, @hoyts1. The issue is that you have more than 1500 store categories (that I can see for sure, you might actually have more than that). For performance reasons we cap the number of categories shown at 1100. This might change in the future as we optimize and improve things, but for now you would need to remove categories in order for any new categories to show. I'm not sure exactly how many categories you have, so I don't know how many you would need to do that with.